1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to CABAC decoding, and more particularly, to decoding a plurality of bin values using a pipeline architecture in a CABAC decoder, and a decoding device therefor.
2. Description of the Related Art
Context-based adaptive binary arithmetic coding (CABAC) is an entropy coding method used in a main profile of H.264/AVC. In CABAC, each symbol is dynamically coded using statistical features to update its relative probability, thereby improving compression efficiency.
CABAC decoding is the process of sequentially decoding a plurality of binary values (0 or 1), or “bins”, from a syntax element (SE) which is encoded by a CABAC encoder. To decode each bin, several unit operations are required, including a context selection operation, a context model loading operation, a binary arithmetic decoding operation, a binarization matching operation, and a context model update operation. The unit operations may each require one cycle.
If each bin is decoded after its previous bin is decoded, then since five cycles are required to decode each bin, 5 n cycles are required to decode n bins. For this reason, real time decoding is impossible in practice when a display device has a standard definition (SD) or larger screen size. Therefore, parallel processing is necessary in this case, in which a plurality of bins are processed at once using a pipeline architecture.